Trek navigator 50 or 100?

I am about to buy a new bike. I haven't riden in awhile and I have pretty much settled on a trek navigator model #50 or 100. the price difference in the store is 230 for the 50 and 300 or the 100. I looked up the trek website but could not get the retail price of the bike. or information on what the difference is between these two. If you have information from personal expierince or know of a good website that would help me with those two things it would be greatly apreciated.
Kevin